Last Sunday, viewers watched a two-hour finale of the ABC fairy tale drama "Once Upon a Time" Season 3, which many hailed as a pleasant ending to a strong season.

In the finale, viewers saw Emma and Hook being pushed into the past and subsequently endeavoring to return to the future. In the process, they were helped by Rumplestiltskin while trying to save Maian, Robin Hood's wife, and getting her back to Storybrooke.

The real shocker, however, was a stowaway from an earlier period, which seemed to be very akin to Elsa from the Oscar-winning animated movie "Frozen." It is expected that this aspect will be looked at quite early in Season 4, which is scheduled for release this fall.

This character appears for just a few seconds in the finale, but there is enough indication that she may turn out to be a villain. The official Tweeter account of the show recently confirmed that it was certainly Elsa, and the picture accompanying said "Frozen is coming to 'Once Upon a Time'."

Viewers also saw Rumple and Belle tying the knot and Snow White and Prince Charming christening their baby Prince Neal to honor Neal. In addition, the finale showed Hook and Emma kissing - perhaps pleasing the fans who have long wanted to see them marry.

In the finale, viewers saw an upset Regina, who is disappointed over Marian being alive. It seems that she has turned somewhat evil again.

It is expected that viewers will see at least one character coming over from "Once Upon a Time in Wonderland" in Season 4.

It is also being speculated that Scarlet, who is also called Knave of Hearts (Michael Socha) will join the series in Season 4.

Producer Adam Horowitz recently told The Hollywood Reporter, "We're very excited about the possibilities for Michael and all the characters."

Co-creator Edward Kitsis said, "He was a member of (Robin Hood's) Merry Men," adding, "We think he'll fit in well in the show."

In all probability, Season 4 will be released sometime in fall this year. While the first season premiered on Oct. 23, the second and third seasons were released in late September. As a result Season 4 is likely to be premiered around the same time.